Nightblood

Whenever a creature dies place a soul counter
on Nightblood. Equipped creature gets +1/+1 for
each soul counter on Nightblood

During upkeep place a -1/-1 counter on equipped creature.

Remove {x} soul counters from Nightblood, place
{x} -1/-1 counters on target creature

Equip {p/b}{p/b}{p/b}